Biomedical subjects
Publications and source records attributed to J Cremer.
We present a case of a 25 year old patient who underwent double-sided lung transplantation and suffered from recurrent pneumonia. Silent aspiration was suspected clinically. Aspiration was proved by scintigraphy enabling to discriminate between direct oro-pulmonal aspiration and aspiration after gastro-esophageal reflux.
Comorbidity of coronary heart disease and carotid stenosis raises the question of surgical stratification. A simultaneous approach of carotid endarterectomy and coronary revascularization, both under conditions of moderate hypothermic extracorporeal circulation, was applied in 48 patients. Considering the complexity of the procedures required the 30-day mortality (2.1%) and perioperative incidence of permanent stroke (2.1%) or myocardial infarction (0%) appeared to be comparably low.
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Following the implantation of Björk Shiley 60 degrees convexo-concave (BS-CC) prostheses, outlet strut fracture rates up to 2.5% per year have been reported. According to experimental results and clinical observations, single leg separations are regarded as the primary mechanisms leading to complete outlet strut fracture after a certain interval. In an experimental study the question was addressed, whether single leg separation can be identified by especially developed radiographic means, before outlet strut fracture occurs. Five BS-CC mitral prostheses (29-31 mm) with intentionally made single leg separations of defined gas sizes (0-75 microns) and one intact mitral prostheses were implanted in sheep in a double-blind study design. Repeat non-invasive investigations were then performed applying a recently developed fluoroscopy imaging technique with direct radiographic magnification (DIMA COR C22). Single leg separations with gap sizes of more than 25 microns were properly detected using DIMA COR C22. Separations 25 microns or less could not be detected with certainty but were evaluated as probable or possible as a result of multiple investigations. The intact prosthesis was correctly identified, but was investigated on only one occasion. Non-invasive control of Björk-Shiley CC mitral prostheses applying especially developed direct radiographic magnification may allow for a reliable assessment of single leg separation with gap sizes of more than 25 microns in sheep. Using this technique of non-invasive serial investigations on particular patients with high probability of outlet strut fracture appears feasible, anticipating single leg separation detectability in humans. This has to be assessed in a second step.(ABSTRACT TRUNCATED AT 250 WORDS)
Infections of vascular prostheses following replacement of the thoracic aorta remain a rare complication, fortunately. The incidence of prosthetic infection amounts to approximately 1.6%, however, there is only limited information from single center studies, and linearized actuarial data for more exact estimations are not available. Experience with prophylaxis and treatment of bacterial endocarditis as well as data available from peripheral vascular reconstruction nevertheless allow the development of treatment strategies concerning this complication. Experimentally, there is clear evidence that pretreatment of Dacron-grafts using the fibrin sealant-antibiotic compound results in a significant protection from infection, created by artificial contamination with staphylococcus aureus. This concept could clearly be confirmed in clinical series involving treatment of prosthetic valve endocarditis. Currently, the concept of implantation of cryopreserved human vascular allografts is studied clinically. Its efficiency in infected areas and following prosthetic replacement of the thoracic aorta has not been proven. Some preliminary results as well as studies on treatment for bacterial endocarditis would suggest a clear advantage of this strategy, however statistically significant improvements have not been published. Currently available data, however, appear to be sufficient to advocate potentially successful techniques as a prophylaxis in routine thoracic aortic replacement as well as for treatment in case of a vascular prosthetic infection following such procedures.
The validity of alternative arterial conduits for myocardial revascularization in comparison to internal thoracic artery (ITA) has not been sufficiently defined. Evaluation of the functional in vivo vascular properties of the different conduits may be appropriate to give a perspective on long-term graft qualities. The intraoperative function of single free grafts to the left anterior descending artery (LAD) was compared in inferior epigastric (IEA, n = 13), internal thoracic (ITA, n = 12) and gastroepiploic artery (GEA, n = 12) conduits. Graft flows were measured at four points of time, 1) in situ free flow after distal dissection (IEA: 42.2 ml/min, ITA: 68.8 ml/min, GEA: 61.1 ml/min), 2) free flow following proximal grafting to the aorta (IEA: 48.1 ml/min, ITA: 63.7 ml/min, GEA: 84.2 ml/min), 3) selective graft flow after distal attachment to the LAD (IEA: 52.6 ml/min, ITA: 77.5 ml/min, GEA: 102.8 ml/min), and 4) selective LAD graft flow following paraverine (Pap) stimulation (IEA: 98.4 ml/min, ITA: 128.0 ml/min, GEA: 142.9 ml/min). Endothelium-dependent and -independent relaxation was evaluated by examination of the intraluminal graft pressures at mechanically controlled constant flow rates. Following stimulation with substance P (SP), the change of intraluminal pressure (dp) was similar in IEA (dp: -20.0 mmHg) and GEA grafts (dp: -21.1 mmHg). Only ITA conduits were less reactive to SP (-9.7 mmHg). The response to acetylcholine (ACh) could only be assessed in ITA (dp: -16.0 mmHg) and IEA (dp: -10.7 mmHg) grafts. Gastroepiploic arteries did not react on ACh stimulation (dp: +0.4 mmHg).(ABSTRACT TRUNCATED AT 250 WORDS)
From published data in the currently available literature on animal experiments, it can be concluded that CyA may be involved in the development of hypertension and renal dysfunction. These side effects are probably related to a disturbed vasomotor tone and a pathologic reaction to physiologic vasoconstrictive and vasodilative agents following administration of high doses of CyA. These effects are dose related and reversible and were undetected at clinically applied levels of immunosuppression. It therefore appears to be unlikely that this pathologic response is operative in precipitating or promoting TCD, which is supported by findings of in vivo and in vitro studies on human coronary arteries as well as by comparison of immunosuppressive protocols comparing series with and without application of CyA. Chronic graft dysfunction, as depicted by late mortality in heart and isolated lung transplant recipients and by loss of kidney allograft survival, yields an annual rate of between 4 and 6% per year. It is only in heart transplantation that TCD has been tried to be associated with CyA application. If CyA-related damage were to occur in coronary arteries independent from immunologic factors, the incidence of coronary disease should be similar in heart, lung, liver, and kidney transplants. This is not the case. Although continuous investigation on the side effects of immunosuppressive agents is definitely necessary, we should concentrate our research activities on potential prophylactic and therapeutic measures to overcome the single most important risk factor of long-term surviving patients after solid organ transplantation: chronic rejection.
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Between 3/91 and 3/93 twenty-nine patients (pts.) with a mean age of 55 years (30-68) underwent CABG (including 3 reoperation) using inferior epigastric artery (IEA) in addition to internal thoracic artery and saphenous vein graft. IEAs were harvested as pedicles with a mean length of 12.2 cm (7.5-17). Overall distal anastomoses were performed 3.2 per patients. And a mean of 2.3 anastomoses were completed as an arterial graft. IEA grafts were applied to left anterior descending artery in 10, diagonal branch in 15, in marginal branches in 2 and right coronary artery in 2. Mean cardiopulmonary bypass time amounted to 103 minutes and operation procedures were completed in 258 minutes (mean). Aortic cross clamp time of 48 minutes were required. One patient was died of cerebral accident 23 days postoperatively. Except for two abdominal wall infection no wound healing problems occurred. One reexploration for bleeding were necessary. Postoperative angiography revealed patent IEA grafts in 12 of 13 patients (92%). We concluded that the application of IEAs for CABG is available as a third arterial graft and with respect to intraoperative management and perioperative complications use of IEA combined with ITAs appears suited or superior to the use of the right gastroepiploic artery.
Borrelia burgdorferi is the causative agent of Lyme borreliosis, a multisystem disorder, which can mimic numerous immune disorders and inflammatory diseases. Laboratory diagnosis of Borrelia infection relies on immunodiagnostic assays, which, however, are hampered by unsatisfactory specificity. The Western blot technique has been employed to analyze the humoral immune response in Lyme borreliosis and is used as a serodiagnostic confirmation test. The most important immunodominant proteins of Borrelia burgdorferi are the 94 kDa, 60 kDa, 41 kDa (flagellin), 34 kDa (Osp B), 31 kDa (Osp A), 30 kDa, 21 kDa (Osp C), and 17/18 kDa proteins. Whereas the 60 kDa, 41 kDa, and 34 kDa constituents reveal a marked cross-antigenicity with other spirochetes and even more distantly related bacteria, antibodies against the 94 kDa, 31 kDa and 21 kDa proteins are largely species-specific. The early immune response in Lyme borreliosis is triggered mainly by the flagellin. In the later stage a wide range of immunogenic proteins is involved, with the 94 kDa antigen being the best marker for late immune response. If the Western blot is used for diagnostic purposes the differences between early and late-stage immunogenicity of Borrelia proteins must be taken into account. Interpretation criteria for blot positivity in early-stage borreliosis are primarily based on the presence of the 21 kDa band and the semiquantitatively recorded intensity of the 41 kDa band. In the diagnosis of late-stage infection, blot positivity relies on the presence of the 94 kDa, 39 kDa, 31 kDa, 30 kDa and 21 kDa bands.
An immunoblot method has been evaluated to diagnose Helicobacter pylori infection serologically by comparing 69 serum specimens from patients with a positive Gram stain and/or culture result and a positive urease test on biopsy material, as well as 51 serum specimens from patients with at least 4 negative urease tests, and negative microscopy and culture results. Sensitivity and specificity was found to be 100%. Recognition of the cross-reacting flagellin (66 kDa), flagellar sheath protein (51 kDa), and a 14 kDa protein are not a criterion for a current H. pylori infection. On the other hand, any combination of at least two of the 180, 120, 90, 75, 67, 29.5 and 19 kDa bands were diagnostic of infection. Three H. pylori strains, which were compared with both gel electrophoretic analyses and immunoblot reactivity, exhibited in part strong qualitative and quantitative differences that particularly affect the 120 kDa pathogenic factor, the large urease subunit and other proteins especially in the molecular mass range from 50 to 67 kDa. IgG immunoblot patterns showed that the choice of H. pylori strain, as well as a reproducible and standardizable antigen preparation, is of great importance for the reliability of serodiagnostic tests. The immunoblot method was found to be a valuable tool for the semi-quantitative confirmation of results achieved with other serological methods as well as optimization and quality control of the antigens used for serodiagnostic purposes.
The plasmid-encoded, released proteins (RPs) of Yersinia enterocolitica serotypes 09 and 03 were separated by sodium dodecyl sulfate (SDS)-pore gradient gel electrophoresis. The RP-patterns of both serotypes proved to be identical. Five major proteins of M(r) 27,000, 34,700, 35,600, 45,800, and 46,800 were detected. Spontaneously plasmid-cured derivatives of the two serotypes lost the feature of protein release. By immunoblotting of RP with sera from patients suffering from acute Yersinia infections, specific and reproducible band patterns were obtained. Laser scan densitometry was applied to record the immunoreactions quantitatively. Predominant bands were detected at an M(r) of 34,700 and 35,600. IgA and IgM antibodies appeared as acute-phase markers rapidly decreasing in the reconvalescent phase. In contrast, immunoblots of patients with supposed chronic yersiniosis were characterized by a persisting IgA and elevated IgG reactivity. The application of RP as diagnostic antigens proved to be advantageous because they are naturally separated from cross-reacting proteins, common to pathogenic and nonpathogenic strains of Yersinia enterocolitica and Y. pseudotuberculosis.
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Vascular responses to endogenous agonists may determine patency rates of bypass graft conduits. The effect of constrictors (noradrenaline, phenylephrine, serotonin, histamine, angiotensin II) and dilators (acetylcholine, substance P, bradykinin, nitroglycerin) were compared in human internal mammary and inferior epigastric arteries in vitro. The latter vessel type has been recently advocated as an additional conduit for coronary artery bypass grafting. Whereas the alpha-adrenoceptor- (noradrenaline, phenylephrine) and serotonin receptor-mediated contractions were similar in both vessels, histamine-induced contractions were greatly enhanced in internal mammary arteries (maximal responses in percent of 80 mmol/L KCl, 131% +/- 15% versus 59% +/- 8%). Maximal contractions in response to angiotensin II were greater in inferior epigastric arteries (50% +/- 6% versus 25% +/- 5%). The endothelium-independent relaxations in response to nitroglycerin were identical in both vessels. In contrast, the endothelium-dependent relaxations in response to acetylcholine, substance P, and bradykinin were significantly greater in the inferior epigastric than in the internal mammary arteries (maximal relaxations expressed as percent of prostaglandin F2 alpha-induced precontraction: acetylcholine, 94% +/- 5% versus 77% +/- 5%; substance P, 85% +/- 4% versus 24% +/- 5%; bradykinin, 77% +/- 5% versus 26% +/- 3%). It is concluded that the inferior epigastric artery has a high endothelial capacity to release endothelium-derived relaxing factor. It appears that the inferior epigastric artery possesses credentials to be successfully used for coronary artery bypass grafting.
The use of the internal thoracic artery (ITA) for coronary bypass grafting (CBG) has resulted in superior long-term function. Other autologous arteries have been investigated also, but the role of the inferior epigastric artery (IEA) for CBG has not yet been defined. From March 91 to August 92, IEA grafts were used in 50 male patients aged 30-68 years/mean 54.9) combined with 1 (n = 40) or 2 (n = 8) ITA grafts. Pedicled grafts were dissected (length: 8.5-16.5, 13.1 cm) but left in situ covered by sponges soaked with papaverine solution until going on bypass. There was no mechanical or pharmacological intraluminal manipulation. Distal free flow (in situ) was 41.8 ml/min (16-95 ml/min). A total of 146 grafts were constructed (2.9/patient), including free IEA-CBG performed to the LAD (n = 28) or its diagonal branches (n = 22). The operative mortality was 2.0%, there were no sternal wound complications but superficial abdominal infections in 5 patients. Recatheterization (1-6 months postoperatively) revealed an 82.6% patency rate (19/23) in IEA, compared to 100% in ITA, grafts. In vitro stimulation of arterial segments by endothelium- or muscular-dependent relaxation revealed a response (% of the maximum) of 92.4% in IEA and 74.6% in ITA to acethylcholine, while the response to nitroglycerin was 92.7% and 98.6%, respectively. Our clinical results would support the concept of combining IEA and ITA for arterial revascularization in CBG. Inferior epigastric artery grafts should provide adequate blood flow and good long-term patency due to preservation of their endothelial function.
Cogan's syndrome has been described as entity of progressive deafness and interstitial keratitis with variable cardiovascular involvement leading to aortic insufficiency or orificial stenosis of coronary or aortic arch vessels. So far, aortic valve replacement either with mechanical or biological prosthesis was favored for correction of the valvular lesion. A patient with primary successful aortic valve repair followed by coronary revascularization for left coronary ostial stenosis occurring after the first operation is presented.
Human parathyroid hormone (hPTH (1-38)) induced concentration-dependent relaxations in prostaglandin F2 alpha-preconstricted pig coronary arteries in vitro. Removal of endothelial cells or pretreatment with nitro-L-arginine, a specific inhibitor of the endothelium-derived relaxing factor (EDRF) synthesis, impaired, although to a small extent, hPTH-induced relaxations. Human PTH-, but not bradykinin- or nitroglycerin-induced relaxations were potentiated in the presence of the cyclic AMP phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX). Human PTH also relaxed preconstricted human inferior epigastric arteries in vitro. In accordance to pig coronary arteries, this relaxation was potentiated in the presence of IBMX. However, the human internal thoracic (mammary) artery did not respond to hPTH (1-100 nM). Thus, acute vasodilatory effects of hPTH may not be present in all human arteries. The physiological significance of this phenomenon is not known. This relaxation, at least in pig arteries, is mediated to a small extent by the release of EDRF. In addition, this relaxation appears to be mainly mediated in both pig and human arteries by a smooth muscle cyclic AMP pathway.